1. Field of the Invention
The present invention relates to a radio communication terminal, a radio base station, and a packet communication method which transmit and receive multiple types of packets.
2. Description of the Related Art
In radio communication systems, it becomes more popular to transmit packets such as a packet including coded voice data which needs transmission delay suppression. In addition to such a type of packets, another type of packets, such as a control packet including control data used for establishing or maintaining communications are also transmitted. The latter type of packets has a low necessity of controlling transmission delay.
To deal with these two types of packets, there is known an approach that sets a first communication session and a second communication session between a radio communication terminal and a communication destination device of the radio communication terminal (see X.S0011-004-D “cdma2000 Wireless IP Network Standard: Quality of Service and Header Reduction” (3GPP2)). The first communication session is a logical communication path used for transmitting a particular type of packet, that is, packet that needs transmission delay suppression. The second communication session is a logical communication path used for transmitting a type of packet different from the particular type of packet.
According to such an approach, QoS control can be performed in which a packet transmitted by using the first communication session has a priority over a packet transmitted by using the second communication session, thereby controlling the transmission delay of the packet transmitted by using the first communication session.
In addition, there has been proposed an approach in which a session identifier to indicate a communication session is added to a header of each packet transmitted by using both a first and a second communication session (see Japanese Patent Application Publication No. 2007-300236).